Bayesian modelling

Dr Richard Staff provides in house Bayesian age-depth modelling of deep time geological sequences using using the OxCal (ver. 4.2) software of Bronk Ramsey (2013) and Bronk Ramsey et al. (2013). This service can be provided for external collaborators - please contact Dr Staff directly to discuss collaboration. 

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As an example application, we have used Bayesian modelling to interrogate the age of geomagnetic events in a sediment core that contained a series of Ar/Ar dated tephra units originating from the Toba caldera (Mark et al., 2017). A ‘P_Sequence’ (i.e., Poisson process) deposition model was applied (Bronk Ramsey, 2008), whereby the deposition rate of the sediment sequence is allowed to vary from that of a constant deposition rate through time (i.e., a uniform ‘U_Sequence’ in OxCal) according to the additional constraint of a parameter, ‘k’ (a higher value of k gives an increasingly linear deposition rate; lower values of k allow increasing flexibility away from a uniform deposition rate). In the context of sediment deposition, the P_Sequence model provides a realistic representation of sediment accumulation, with the complexity (randomness) of the underlying deposition modelled according to a Poisson process. The k parameter is not fixed a priori, allowing the program itself to determine an unbiased measure of the rigidity of the deposition rate, based upon the dating (‘likelihood’) information combined within the P_Sequence model prior (Bronk Ramsey and Lee, 2013).

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Bayesian modelling is currently utilised to underpin geochronological models of Large Igneous Province development (coming soon), including the Siberian Traps and British Palaeogene Igneous Province.